Orbitalt impulsmoment (bølge): Forskelle mellem versioner

== Snoede radiobølger ==

En snoet radiobølge kan laves med fx flere radioantenner.<ref>[https://arxiv.org/abs/1507.06889 Experimental near field OAM-based communication with circular patch array], [https://arxiv.org/pdf/1507.06889.pdf pdf] Citat: "...In fact, OAM waves do not interact during propagation in a homogeneous medium, i.e., they form an orthogonal set of propagating modes [8]...Circular arrays composed by elementary dipoles [6], patches [23], [24] or Vivaldi antennas [25], have been simulated for OAM generation...Fig. 15. Maps of reception zones for multi-channels OAM based communication system (A), (C) and for single channel traditional ones (B), (D). Vertical axis reports the distance between Tx and Rx arrays. Horizontal axis indicates lateral shift (A), (B) or angular tilt (C), (D) between Rx and Tx array. Red areas indicates physical space where the Rx array receives three channels. In yellow and green areas at most two channels can be correctly received...We designed two circular arrays, composed by patch antennas, in order to generate and detect OAM modes with l=−1,0,+1 value, at the frequency of 5.75GHz. A very good agreement with theoretical predictions is found..."</ref>

 

De fire antenner kan enten placeres i en firkantnet, så antennerne i strålingsretningen er 0, 90, 180 og 270 grader forskudt (OAM +1). 0, -90, -180 og -270 grader forskudt (OAM -1). Har de alle fire 0 grader i strålingsretningen, sendes med OAM=0.